We have a business environment in which we have 3 Cisco 3850 PoE stacked and We manage our DHCP through our DC server.
Last weekend our UPS had a failure and switched off all outputs, so all the equipment has been reset since then.
On Monday I started noticing that first, I lost ping to a card reader that had been working fine until now. And sencond and most important: every new computer we plug into our network resolves DHCP fine but has no ping to our GW.
So here's what I know:
- DHCP requests go through just fine, I can see the new computer's records in our DHCP server.
- Ping works fine to other computers in the same Vlan/subnet, but I get 0 response from the Gateway
- With wireshark I could see that these computers spam ARP packets asking for our Gateway with 0 response
- I flushed my own ARP cache and I actually got a response from the ARP request first try
- If I use an USB network card from another computer that was already working, it works no problem, until today for some reason
- The MAC table in the switch has been flushed already
- Wi-Fi works OK, we have it on a different Vlan but similar setup with the same DHCP server.
Any ideas? I googled the hell out of it and I found no one with the same issue.
Thanks in advance!